1. Field of the Invention
This invention relates to an image projecting apparatus such as for a reader-printer, adapted to allow a cartridge containing a microfilm to be automatically loaded in the image projecting apparatus.
2. Description of the Prior Art
A microfilm reader is used for the purpose of projecting in a magnified scale an image recorded on a microfilm onto a screen and allowing inspection of the projected image. A microfilm reader-printer is possessed of the function of copying such an image in addition to the function of projecting the image. A microfilm scanner reads the image of the microfilm by means of CCD, a solid image pickup device.
Generally, microfilms are stored in large bulk and readied for use. At the time of use of the particular frame of a microfilm containing a desired image, it is required to retrieve the frame and copy the image expeditiously. Heretofore, for the purpose of retrieving and copying a desired image frame in a microfilm as with the reader-printer, it has been customary to load the cartridges containing a roll of microfilm manually one after another in the roll film carrier of the reader-printer and, after use, remove them manually from the reader-printer. To be specific, each time the retrieving and copying steps are completed on each cartridge, the operator is required manually to remove the cartridge from and load the next cartridge in the the reader-printer, namely to interchange the cartridges. Thus, the problem that the interchange of cartridges calls for time and labor and consequently renders it difficult to carry out the steps of retrieving and copying an image frame of microfilm expeditiously has been pointed out.
As measures to cope with the problems of this nature, cartridge loaders, i.e. automatic loading devices for cartridges containing a roll of microfilm have been developed recently. Such a cartridge loader is attached as an auxiliary device to the reader-printer, for example. The cartridge loader automatically extracts necessary cartridges one after another from a cartridge container and loads them in the roll film carrier. When the retrieving and copying steps are completed on a microfilm, the cartridge loader extracts the used cartridge from the roll film carrier and returns it to the cartridge container. The roll film carrier is provided with a supply part. In the supply part, the cartridge is loaded as position so as to allow loading of the microfilm in the cartridge. Incidentally, in the conventional supply part, the front surface part on the cartridge loading side is constructed immovably relative to the path through which the cartridge is loaded.
It has been pointed out, however, that the conventional system entails the following problem. Generally, in the cartridge loader and the roll film carrier, a loading path intended for newly loading a cartridge of microfilm to be used and a discharge path intended for extracting and returning the used cartridge after completion of the retrieving and copying steps are formed. In the conventional cartridge loader or roll film carrier, however, the loading path and the discharge path have been formed so as to overlap each other at least partly and not separate completely from each other. Owing to the partial coincidence between the loading path and the discharge path, the loading of the next cartridge must wait until the extraction of the used cartridge is completed. As a result, the interchange of cartridges has called for a long time and posed itself a problem. The automatic cartridge loader, in spite of the automated cartridge loading, has the possibility of consuming nearly as much time as the conventional manual method of interchange of cartridges. It has been pointed out that the long time thus spent for the interchange of cartridges poses a hindrance in the way of expeditious performance of the retrieving and copying steps on the microfilm.
Further, the following problem has been also pointed out. For the conventional cartridge loader, since the retrieving and copying steps have not yet been performed on the individual cartridges stored in the cartridge container, it is not easy to discriminate between the cartridges which are to be loaded in the supply part of the roll film carrier and the cartridges which have undergone the retrieving and copying steps and have been returned as already used. The discernment of the identity of cartridges as used ones or otherwise calls for much time. It has been pointed out, therefore, that the discrimination poses a hindrance in the way of expeditious performance of the retrieving and copying steps on the microfilm.
The first method developed for discriminating or discerning given cartridges as used ones or otherwise comprises having an image management code (IMC) read in preparatorily in a microfilm and subsequently allowing discernment of a cartridge as a used one or otherwise by presence or absence of the detection of the IMC in the microfilm. This method, however, requires to load microfilms one by one in the roll film carrier and examine them to discriminate between presence and absence of the IMC therein. This examination necessitates wasteful time and, after all, entails the problem that the object of effecting the retrieving and copying steps expeditiously is not fulfilled. The second method developed for the same purpose comprises having a detection tape or detection mark attached preparatorily on cartridges and subsequently allowing discernment of a cartridge as a used one or otherwise by presence or absence of the detection of the tape or mark. This method, however, entails the problem that the application of the tape or mark to the cartridge adds to the number of steps of operation and raises the cost proportionately. Further, this method requires to install an exclusive mechanism for the detection of the tape and consequently complicates the construction of the system, sacrifices reliability of performance of the system, and increases the cost.
It has been pointed out that the conventional cartridge loader encounters the following problem. The cartridge loaded in the roll film carrier cannot be taken out until the the microfilm contained therein has been completely retrieved and then has been completely rewound. The conventional cartridge loader is adapted so that the motion for the removal of the cartridge is not commenced until after the cartridge has been readied for extraction as described above. Then, the cartridge loader catches hold of the used cartridge, extracts it from the roll film carrier, and loads the next new cartridge in the roll film carrier. In other words, the conventional cartridge loader waits until each cartridge loaded in the roll film carrier has been used and then readied for removal and thereafter performs the work for removal of the used cartridge and the work of loading a new cartridge. It has been pointed out, therefore, that the conventional cartridge loader still calls for much time for the interchange of cartridges. For the purpose of expediting the retrieving and copying steps to be performed on the microfilm, therefore, the conventional cartridge loader has been expected to allow a further reduction in the time to be spent for the interchange of cartridges.
The following problem has been also pointed out. The cartridge container produces the action of causing cartridges stored in the cartridge container to be loaded in the roll film carrier and the action of causing the cartridges loaded in the roll film carrier to be returned to the cartridge container. For the purpose of stopping these actions of the cartridge loader, it has been necessary to detect the fact that the retrieving and copying steps have been completed on the microfilm in the last of the cartridges stored in the cartridge container and this particular cartridge has been returned from the roll film carrier, namely the fact that the retrieving and copying steps have been completed on .the microfilms in all the cartridges stored in the cartridge container. For the cartridge loader to stop the actions of itself, it is required to detect the fact that the retrieving and copying actions have been wholly completed as described above. This requirement has posed a problem in the way to automation of the retrieving and copying steps to be performed on the microfilm.
The following problem has been also pointed out. The roll film carrier is generally adapted to produce a vertical scanning motion for correction of the positional deviation of the image in the vertical direction during the retrieving and copying steps being performed on the microfilm in the loaded cartridge. To be specific, it often happens that for the purpose of moving the image in the microfilm in the vertical direction on the screen, the vertical scanning for slightly moving the roll film carrier in the longitudinal direction, for example, relative to the main body of the system such as the reader-printer. When the roll film carrier is located at the home position which is the neutral position, the axis of the projected light on the main body of the system falls on the central line of film along the longitudinal direction of the roll microfilm. Further, the roll film carrier is located at the standard position at which it cooperates with the cartridge loader in performing the steps of loading and returning cartridges. When the vertical scanning is carried out, the roll film carrier inevitably deviates from the home position mentioned above. When the interchange of cartridges namely the return of a used cartridge and the loading of the next new cartridge are carried out, it has been necessary for the roll film carrier to be returned to the home position each time the positional deviation caused by the vertical scanning is to be corrected. It has been pointed out that the interchange of individual cartridges does not smoothly proceed and this inconvenience has posed a hindrance in the way of automation of the retrieving and copying steps to be performed on the microfilm. Further, the interchange of cartridges consumes much time and this fact has prevented the retrieving and copying steps from being performed expeditiously.
Further, the following problem has been pointed out. While cartridges are being stored in the cartridge container of the cartridge loader, they must be introduced therein in a prescribed correct direction. It often happens, however, that cartridges mistaken in their longitudinal, lateral, or vertical directions will be set in wrong directions. When the cartridges are set in wrong directions, they are liable to sustain damage and inflict damage to the roll film carrier and entail troubles such as mistaken retrieval. The precautions to be used accordingly cost time and labor and entail loss of time. It has been pointed out that this loss of time poses a hindrance to the retrieving and copying steps to be performed on the microfilm.